The invention relates to a device for determining the static pressure of a patient, wherein the device comprises a pump connected to a patient line for conveying a dialysis solution into the abdomen of the patient, as well as blocking means, in particular a valve, via which the patient line can be blocked, wherein the device has a pressure chamber that is fluidically connected to the patient line when the blocking element is open, wherein a pressure measuring unit is further provided, which is arranged in such a way that it measures the pressure in the pressure chamber or a pressure correlating with same, wherein the device has a control unit which is designed in such a way that, in a first step, it brings about a pressure increase in the pressure chamber up to a measuring pressure, and in a second step, it opens the blocking element, such that the measuring pressure in the pressure chamber is applied to the patient line or a sub-section of same, and wherein the device has an evaluation unit which evaluates the measured pressure after the opening of the blocking element.
